SMB

Server Message Block (SMB) es un protocolo cliente-servidor que regula el acceso a archivos y directorios completos y a otros recursos de red como impresoras, routers o interfaces liberadas para la red. El intercambio de información entre distintos procesos del sistema también puede gestionarse basándose en el protocolo SMB. SMB se puso por primera vez a disposición de un público más amplio, por ejemplo, como parte del sistema operativo de red OS/2 LAN Manager y LAN Server. Desde entonces, la principal área de aplicación del protocolo ha sido la serie de sistemas operativos Windows en particular, cuyos servicios de red soportan SMB de forma compatible con versiones anteriores, lo que significa que los dispositivos con ediciones más recientes pueden comunicarse fácilmente con dispositivos que tengan instalado un sistema operativo Microsoft más antiguo. Con el proyecto de software libre Samba, también existe una solución que permite el uso de SMB en distribuciones Linux y Unix y, por tanto, la comunicación multiplataforma a través de SMB.

Vemos la configuración global y dos recursos compartidos destinados a impresoras. Los ajustes globales son la configuración del servidor SMB disponible que se utiliza para todos los recursos compartidos. En los recursos compartidos individuales, sin embargo, se pueden sobrescribir los ajustes globales, que se pueden configurar con alta probabilidad incluso incorrectamente. Veamos algunos de los ajustes para entender cómo se configuran los recursos compartidos en Samba.

Configuración	Descripción
[sharename]	El nombre del recurso compartido de red.
workgroup = WORKGROUP/DOMAIN	Grupo de trabajo que aparecerá cuando los clientes consulten.
path = /path/here/	El directorio al que se le dará acceso al usuario.
server string = STRING	La cadena que aparecerá cuando se inicie una conexión.
unix password sync = yes	¿Sincronizar la contraseña de UNIX con la contraseña de SMB?
usershare allow guests = yes	¿Permitir que los usuarios no autenticados accedan al recurso compartido definido?
map to guest = bad user	¿Qué hacer cuando la solicitud de inicio de sesión de un usuario no coincide con un usuario UNIX válido?
browseable = yes	¿Esta acción debería aparecer en la lista de acciones disponibles?
guest ok = yes	¿Permitir conectarse al servicio sin usar contraseña?
read only = yes	¿Permitir a los usuarios leer solo archivos?
create mask = 0700	¿Qué permisos se deben establecer para los archivos recién creados?

Dangerous Settings

Configuración	Descripción
browseable = yes	¿Permitir listar acciones disponibles en la acción actual?
read only = no	¿Prohibir la creación y modificación de archivos?
writable = yes	¿Permitir a los usuarios crear y modificar archivos?
guest ok = yes	¿Permitir conectarse al servicio sin usar contraseña?
enable privileges = yes	¿Respetar los privilegios asignados a un SID específico?
create mask = 0777	¿Qué permisos se deben asignar a los archivos recién creados?
directory mask = 0777	¿Qué permisos se deben asignar a los directorios recién creados?
logon script = script.sh	¿Qué script debe ejecutarse al iniciar sesión el usuario?
magic script = script.sh	¿Qué script debe ejecutarse cuando se cierra el script?
magic output = script.out	¿Dónde se debe almacenar la salida del script mágico?

SMBclient - Connecting to the Share

smbclient -N -L //10.129.14.128

        Sharename       Type      Comment
        ---------       ----      -------
        print$          Disk      Printer Drivers
        home            Disk      INFREIGHT Samba
        dev             Disk      DEVenv
        notes           Disk      CheckIT
        IPC$            IPC       IPC Service (DEVSM)
SMB1 disabled -- no workgroup available

smbclient //10.129.14.128/notes

Enter WORKGROUP\<username>'s password: 
Anonymous login successful
Try "help" to get a list of possible commands.


smb: \> help

Download Files from SMB

smb: \> get prep-prod.txt 

getting file \prep-prod.txt of size 71 as prep-prod.txt (8,7 KiloBytes/sec) 
(average 8,7 KiloBytes/sec)


smb: \> !ls

prep-prod.txt


smb: \> !cat prep-prod.txt

[] check your code with the templates
[] run code-assessment.py
[] …	

RPCclient

rpcclient -U "" 10.129.14.128

Enter WORKGROUP\'s password:
rpcclient $> 

Query	Description
srvinfo	Server information.
enumdomains	Enumerate all domains that are deployed in the network.
querydominfo	Provides domain, server, and user information of deployed domains.
netshareenumall	Enumerates all available shares.
netsharegetinfo <share>	Provides information about a specific share.
enumdomusers	Enumerates all domain users.
queryuser <RID>	Provides information about a specific user.

RPCclient - Enumeration

rpcclient $> srvinfo

        DEVSMB         Wk Sv PrQ Unx NT SNT DEVSM
        platform_id     :       500
        os version      :       6.1
        server type     :       0x809a03
		
		
rpcclient $> enumdomains

name:[DEVSMB] idx:[0x0]
name:[Builtin] idx:[0x1]


rpcclient $> querydominfo

Domain:         DEVOPS
Server:         DEVSMB
Comment:        DEVSM
Total Users:    2
Total Groups:   0
Total Aliases:  0
Sequence No:    1632361158
Force Logoff:   -1
Domain Server State:    0x1
Server Role:    ROLE_DOMAIN_PDC
Unknown 3:      0x1


rpcclient $> netshareenumall

netname: print$
        remark: Printer Drivers
        path:   C:\var\lib\samba\printers
        password:
netname: home
        remark: INFREIGHT Samba
        path:   C:\home\
        password:
netname: dev
        remark: DEVenv
        path:   C:\home\sambauser\dev\
        password:
netname: notes
        remark: CheckIT
        path:   C:\mnt\notes\
        password:
netname: IPC$
        remark: IPC Service (DEVSM)
        path:   C:\tmp
        password:
		
		
rpcclient $> netsharegetinfo notes

netname: notes
        remark: CheckIT
        path:   C:\mnt\notes\
        password:
        type:   0x0
        perms:  0
        max_uses:       -1
        num_uses:       1
revision: 1
type: 0x8004: SEC_DESC_DACL_PRESENT SEC_DESC_SELF_RELATIVE 
DACL
        ACL     Num ACEs:       1       revision:       2
        ---
        ACE
                type: ACCESS ALLOWED (0) flags: 0x00 
                Specific bits: 0x1ff
                Permissions: 0x101f01ff: Generic all access SYNCHRONIZE_ACCESS WRITE_OWNER_ACCESS WRITE_DAC_ACCESS READ_CONTROL_ACCESS DELETE_ACCESS 
                SID: S-1-1-0

Rpcclient - User Enumeration

rpcclient $> enumdomusers

user:[mrb3n] rid:[0x3e8]
user:[cry0l1t3] rid:[0x3e9]


rpcclient $> queryuser 0x3e9

        User Name   :   cry0l1t3
        Full Name   :   cry0l1t3
        Home Drive  :   \\devsmb\cry0l1t3
        Dir Drive   :
        Profile Path:   \\devsmb\cry0l1t3\profile
        Logon Script:
        Description :
        Workstations:
        Comment     :
        Remote Dial :
        Logon Time               :      Do, 01 Jan 1970 01:00:00 CET
        Logoff Time              :      Mi, 06 Feb 2036 16:06:39 CET
        Kickoff Time             :      Mi, 06 Feb 2036 16:06:39 CET
        Password last set Time   :      Mi, 22 Sep 2021 17:50:56 CEST
        Password can change Time :      Mi, 22 Sep 2021 17:50:56 CEST
        Password must change Time:      Do, 14 Sep 30828 04:48:05 CEST
        unknown_2[0..31]...
        user_rid :      0x3e9
        group_rid:      0x201
        acb_info :      0x00000014
        fields_present: 0x00ffffff
        logon_divs:     168
        bad_password_count:     0x00000000
        logon_count:    0x00000000
        padding1[0..7]...
        logon_hrs[0..21]...


rpcclient $> queryuser 0x3e8

        User Name   :   mrb3n
        Full Name   :
        Home Drive  :   \\devsmb\mrb3n
        Dir Drive   :
        Profile Path:   \\devsmb\mrb3n\profile
        Logon Script:
        Description :
        Workstations:
        Comment     :
        Remote Dial :
        Logon Time               :      Do, 01 Jan 1970 01:00:00 CET
        Logoff Time              :      Mi, 06 Feb 2036 16:06:39 CET
        Kickoff Time             :      Mi, 06 Feb 2036 16:06:39 CET
        Password last set Time   :      Mi, 22 Sep 2021 17:47:59 CEST
        Password can change Time :      Mi, 22 Sep 2021 17:47:59 CEST
        Password must change Time:      Do, 14 Sep 30828 04:48:05 CEST
        unknown_2[0..31]...
        user_rid :      0x3e8
        group_rid:      0x201
        acb_info :      0x00000010
        fields_present: 0x00ffffff
        logon_divs:     168
        bad_password_count:     0x00000000
        logon_count:    0x00000000
        padding1[0..7]...
        logon_hrs[0..21]...

Rpcclient - Group Information

rpcclient $> querygroup 0x201

        Group Name:     None
        Description:    Ordinary Users
        Group Attribute:7
        Num Members:2

Brute Forcing User RIDs

for i in $(seq 500 1100);do rpcclient -N -U "" 10.129.14.128 -c "queryuser 0x$(printf '%x\n' $i)" | grep "User Name\|user_rid\|group_rid" && echo "";done

        User Name   :   sambauser
        user_rid :      0x1f5
        group_rid:      0x201
		
        User Name   :   mrb3n
        user_rid :      0x3e8
        group_rid:      0x201
		
        User Name   :   cry0l1t3
        user_rid :      0x3e9
        group_rid:      0x201

Impacket - Samrdump.py

samrdump.py 10.129.14.128

Impacket v0.9.22 - Copyright 2020 SecureAuth Corporation

[*] Retrieving endpoint list from 10.129.14.128
Found domain(s):
 . DEVSMB
 . Builtin
[*] Looking up users in domain DEVSMB
Found user: mrb3n, uid = 1000
Found user: cry0l1t3, uid = 1001
mrb3n (1000)/FullName: 
mrb3n (1000)/UserComment: 
mrb3n (1000)/PrimaryGroupId: 513
mrb3n (1000)/BadPasswordCount: 0
mrb3n (1000)/LogonCount: 0

SMBmap

smbmap -H 10.129.14.128

[+] Finding open SMB ports....
[+] User SMB session established on 10.129.14.128...
[+] IP: 10.129.14.128:445       Name: 10.129.14.128                                     
        Disk                                                    Permissions     Comment
        ----                                                    -----------     -------
        print$                                                  NO ACCESS       Printer Drivers
        home                                                    NO ACCESS       INFREIGHT Samba
        dev                                                     NO ACCESS       DEVenv
        notes                                                   NO ACCESS       CheckIT
        IPC$                                                    NO ACCESS       IPC Service (DEVSM)

CrackMapExec

crackmapexec smb 10.129.14.128 --shares -u '' -p ''

SMB         10.129.14.128   445    DEVSMB           [*] Windows 6.1 Build 0 (name:DEVSMB) (domain:) (signing:False) (SMBv1:False)
SMB         10.129.14.128   445    DEVSMB           [+] \: 
SMB         10.129.14.128   445    DEVSMB           [+] Enumerated shares
SMB         10.129.14.128   445    DEVSMB           Share           Permissions     Remark
SMB         10.129.14.128   445    DEVSMB           -----           -----------     ------
SMB         10.129.14.128   445    DEVSMB           print$                          Printer Drivers
SMB         10.129.14.128   445    DEVSMB           home                            INFREIGHT Samba
SMB         10.129.14.128   445    DEVSMB           dev                             DEVenv
SMB         10.129.14.128   445    DEVSMB           notes           READ,WRITE      CheckIT
SMB         10.129.14.128   445    DEVSMB           IPC$                            IPC Service (DEVSM)

Enum4Linux-ng - Installation

./enum4linux-ng.py 10.129.14.128 -A

ENUM4LINUX - next generation

 ==========================
|    Target Information    |
 ==========================
[*] Target ........... 10.129.14.128
[*] Username ......... ''
[*] Random Username .. 'juzgtcsu'
[*] Password ......... ''
[*] Timeout .......... 5 second(s)

 =====================================
|    Service Scan on 10.129.14.128    |
 =====================================
[*] Checking LDAP
[-] Could not connect to LDAP on 389/tcp: connection refused
[*] Checking LDAPS
[-] Could not connect to LDAPS on 636/tcp: connection refused
[*] Checking SMB
[+] SMB is accessible on 445/tcp
[*] Checking SMB over NetBIOS
[+] SMB over NetBIOS is accessible on 139/tcp

 =====================================================
|    NetBIOS Names and Workgroup for 10.129.14.128    |
 =====================================================
[+] Got domain/workgroup name: DEVOPS
[+] Full NetBIOS names information:
- DEVSMB          <00> -         H <ACTIVE>  Workstation Service
- DEVSMB          <03> -         H <ACTIVE>  Messenger Service
- DEVSMB          <20> -         H <ACTIVE>  File Server Service
- ..__MSBROWSE__. <01> - <GROUP> H <ACTIVE>  Master Browser
- DEVOPS          <00> - <GROUP> H <ACTIVE>  Domain/Workgroup Name
- DEVOPS          <1d> -         H <ACTIVE>  Master Browser
- DEVOPS          <1e> - <GROUP> H <ACTIVE>  Browser Service Elections
- MAC Address = 00-00-00-00-00-00

 ==========================================
|    SMB Dialect Check on 10.129.14.128    |
 ==========================================
[*] Trying on 445/tcp
[+] Supported dialects and settings:
SMB 1.0: false
SMB 2.02: true
SMB 2.1: true
SMB 3.0: true
SMB1 only: false
Preferred dialect: SMB 3.0
SMB signing required: false

 ==========================================
|    RPC Session Check on 10.129.14.128    |
 ==========================================
[*] Check for null session
[+] Server allows session using username '', password ''
[*] Check for random user session
[+] Server allows session using username 'juzgtcsu', password ''
[H] Rerunning enumeration with user 'juzgtcsu' might give more results

 ====================================================
|    Domain Information via RPC for 10.129.14.128    |
 ====================================================
[+] Domain: DEVOPS
[+] SID: NULL SID
[+] Host is part of a workgroup (not a domain)

 ============================================================
|    Domain Information via SMB session for 10.129.14.128    |
 ============================================================
[*] Enumerating via unauthenticated SMB session on 445/tcp
[+] Found domain information via SMB
NetBIOS computer name: DEVSMB
NetBIOS domain name: ''
DNS domain: ''
FQDN: htb

 ================================================
|    OS Information via RPC for 10.129.14.128    |
 ================================================
[*] Enumerating via unauthenticated SMB session on 445/tcp
[+] Found OS information via SMB
[*] Enumerating via 'srvinfo'
[+] Found OS information via 'srvinfo'
[+] After merging OS information we have the following result:
OS: Windows 7, Windows Server 2008 R2
OS version: '6.1'
OS release: ''
OS build: '0'
Native OS: not supported
Native LAN manager: not supported
Platform id: '500'
Server type: '0x809a03'
Server type string: Wk Sv PrQ Unx NT SNT DEVSM

 ======================================
|    Users via RPC on 10.129.14.128    |
 ======================================
[*] Enumerating users via 'querydispinfo'
[+] Found 2 users via 'querydispinfo'
[*] Enumerating users via 'enumdomusers'
[+] Found 2 users via 'enumdomusers'
[+] After merging user results we have 2 users total:
'1000':
  username: mrb3n
  name: ''
  acb: '0x00000010'
  description: ''
'1001':
  username: cry0l1t3
  name: cry0l1t3
  acb: '0x00000014'
  description: ''

 =======================================
|    Groups via RPC on 10.129.14.128    |
 =======================================
[*] Enumerating local groups
[+] Found 0 group(s) via 'enumalsgroups domain'
[*] Enumerating builtin groups
[+] Found 0 group(s) via 'enumalsgroups builtin'
[*] Enumerating domain groups
[+] Found 0 group(s) via 'enumdomgroups'

 =======================================
|    Shares via RPC on 10.129.14.128    |
 =======================================
[*] Enumerating shares
[+] Found 5 share(s):
IPC$:
  comment: IPC Service (DEVSM)
  type: IPC
dev:
  comment: DEVenv
  type: Disk
home:
  comment: INFREIGHT Samba
  type: Disk
notes:
  comment: CheckIT
  type: Disk
print$:
  comment: Printer Drivers
  type: Disk
[*] Testing share IPC$
[-] Could not check share: STATUS_OBJECT_NAME_NOT_FOUND
[*] Testing share dev
[-] Share doesn't exist
[*] Testing share home
[+] Mapping: OK, Listing: OK
[*] Testing share notes
[+] Mapping: OK, Listing: OK
[*] Testing share print$
[+] Mapping: DENIED, Listing: N/A

 ==========================================
|    Policies via RPC for 10.129.14.128    |
 ==========================================
[*] Trying port 445/tcp
[+] Found policy:
domain_password_information:
  pw_history_length: None
  min_pw_length: 5
  min_pw_age: none
  max_pw_age: 49710 days 6 hours 21 minutes
  pw_properties:
  - DOMAIN_PASSWORD_COMPLEX: false
  - DOMAIN_PASSWORD_NO_ANON_CHANGE: false
  - DOMAIN_PASSWORD_NO_CLEAR_CHANGE: false
  - DOMAIN_PASSWORD_LOCKOUT_ADMINS: false
  - DOMAIN_PASSWORD_PASSWORD_STORE_CLEARTEXT: false
  - DOMAIN_PASSWORD_REFUSE_PASSWORD_CHANGE: false
domain_lockout_information:
  lockout_observation_window: 30 minutes
  lockout_duration: 30 minutes
  lockout_threshold: None
domain_logoff_information:
  force_logoff_time: 49710 days 6 hours 21 minutes

 ==========================================
|    Printers via RPC for 10.129.14.128    |
 ==========================================
[+] No printers returned (this is not an error)

Completed after 0.61 seconds